Fluid pumping device and components with static seal

ABSTRACT

A static seal structure for a pump housing includes a support structure, a first sealing element, and a second sealing element. The support structure circumscribes a pump chamber and includes a first sealing surface, an opposing second sealing surface, and a fluid transfer end interposed between the sealing surfaces. The support structure provides a fluid flow path running through the fluid transfer end and into the pump chamber via an inlet bore and from the pump chamber back through the fluid transfer end via an outlet bore. The first sealing element is disposed on the first sealing surface, and the second sealing element is disposed on the second sealing surface. The sealing elements are configured for forming sealing interfaces in the pump housing, establishing a static seal that isolates the pump chamber from an environment external to the fluid pump housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional patent application of U.S.Non-Provisional patent application Ser. No. 12/412,300 titled “FluidPumping Device and Components with Static Seal,” filed on Mar. 26, 2009which claims priority to U.S. Provisional Patent Application Ser. No.61/040,615 titled “Device For Hermetically Sealing A Ventricular AssistDevice Chamber,” filed on Mar. 28, 2008, both of which are incorporatedby reference in their entireties into this application.

TECHNICAL FIELD

The present invention generally relates to static seals and enclosuresand devices utilizing static seals. As one particular example, thepresent invention relates to fluid pumping devices utilizing staticseals such as ventricular assist devices.

BACKGROUND

In fluid pumping devices requiring the assembly of two or morecomponents together, static seals may be utilized to prevent unwantedfluid leakage or flow at the interface between assembled components.Moreover, such fluid pumping devices may include internal regions thatneed to be maintained at a certain pressure or at least without the lossof pressure. Static seals may be utilized to prevent fluid leakage andpressure loss. Fluid pumping devices utilizing static seals includeVentricular Assist Devices (VADs), which are utilized as circulatorysupport devices for patients during or after open heart surgery or as abridge to heart transplant for cardiac-failure patients. Othercirculatory support devices include rotary blood pumps and axial bloodpumps.

Typically, circulatory support devices include some type of a pumpingunit, or components configured to provide a pumping action, contained ina suitable enclosure. The pumping unit of the circulatory support devicemay be connected to a patient's heart via cannulae attached to the heartat appropriate locations according to known surgical practices.Particularly in the case of a VAD, the pumping unit may include aflexible blood sac for supporting or replacing heart activity. The bloodsac may be attached to an input cannula via a one-way input valve and toan output cannula via a one-way output valve. The enclosure for theblood sac may be provided in the form of two half shells that arecoupled together to enclose the blood sac, resulting in an assembledVAD. A sealing element is included at the interface of the two halfshells to hermetically seal the interior (containing the blood sac) fromthe environment external to the assembled VAD. The sealing element istypically constructed from a deformable material, while the half shellsare rigid. Upon coupling the half shells together with the deformablesealing element therebetween, the half shells exert pressure on thesealing element. Consequently, the sealing element is compressed andessentially fills in (or conforms to) the interface between the halfshells, thereby establishing a static seal. In the case where a flexibleblood sac is employed as the pumping unit, one of the half shells mayprovide a fitting configured for connection to a pneumatic drive unit.The pneumatic drive unit may be operated to provide air or other gas tothe interior of the enclosure in pulses (or fluctuating levels ofpressure). In response to a pulse of air input, the blood sac iscompressed (e.g., collapses, contracts, etc.), thereby pumping bloodresiding within the blood sac through the output cannula. Betweenpulses, the blood sac relaxes or expands to enable blood to fill theblood sac from the input cannula.

FIG. 1 is an exploded perspective view of a VAD 100 as described in U.S.Pat. No. 7,217,236 commonly assigned to the assignee of the presentdisclosure and incorporated herein by reference in its entirety intothis application. The VAD 100 includes a disposable pumping unit 120housed within 122 having an inlet 132 and outlet 134 respectivelyattached to a disposable one-way inlet valve 126 and outlet valve 124.Tubing connectors 130 and 128 are respectively attached to the inletvalve 126 and outlet valve 124 as interfaces to cannulae (not shown).The pump shell 112 includes an upper clamshell half 114 and a lowerclamshell half 116. When assembled together, the upper clamshell half114 and the lower clamshell half 116 define a pump chamber 142 in whichthe blood sac 122 resides. The lower clamshell half 116 has an air inlet138 for connection to a pneumatic drive unit (not shown). The pneumaticdrive unit provides a pulsed flow of air to the pump chamber 142 via theair inlet 138, thereby alternating the air pressure in the pump chamber142 between high and low levels. In response, the blood sac 122alternately contracts and expands such that blood is pumped along a flowpath from the input tubing connector 130, to the inlet valve 126, theinterior of the blood sac 122, the outlet valve 124, and to the outputtubing connector 128.

In the VAD 100 illustrated in FIG. 1, a static, hermetic seal is formedat least in part by a disposable sealing element 118. The sealingelement 118 is located along the plane of the interface between theupper clamshell half 114 and the lower clamshell half 116. Stated inanother way, the sealing element 118 is located at the assembly plane ofthe two-piece pump shell 112 where the respective assembly faces of theupper clamshell half 114 and the lower clamshell half 116 meet. Theconfiguration of the VAD 100, however, makes the ability of this sealingelement 118 to consistently provide a hermetic seal at the assemblyplane without pressure loss challenging. The configuration of the VAD100 is characterized by the inlet and outlet fluidic lines being locatedon the same assembly plane as the faces of the upper clamshell half 114and the lower clamshell half 116. Thus, as shown in FIG. 1, the inlet132 and outlet 134 of the blood sac 122, the inlet valve 126 and theoutlet valve 124, the tubing connectors 130 and 128, and the input andoutput cannulae (not shown) are all positioned essentially at theassembly plane between the upper clamshell half 114 and the lowerclamshell half 116. Moreover, the tubing connectors 130 and 132 arelocated proximate to each other on the same side of the VAD 100.

Generally, this configuration for the VAD 100 may be considered asoptimal for a variety of reasons. For instance, a surgeon can easilyvisualize and remember which tubing connectors 130 and 132 are beingutilized for the input and output directions of blood flow,respectively. If the cannulae are initially connected to the wrongtubing connectors 130 and 132, the surgeon can easily switch theconnections. Moreover, the inputs and outputs to the device are easilyobservable in one location to determine whether the blood sac 122 or oneof the valves 124 and 126 has failed. In addition, assembly anddisassembly of the VAD 100 for the purpose of replacing the blood sac122 or the valves 124 and 126 is thought to be facilitated by thisconfiguration. Ease of assembly and disassembly is particularlyimportant during surgery. However, the configuration illustrated in FIG.1 requires complex geometry, particularly with regard to varioussurfaces within the interior of the VAD 100. The valves 124 and 126 andtubing connectors 128 and 130 are accommodated by a cylindrical inletregion 146, a cylindrical outlet region 144, and associated grooves,surfaces, edges, and the like. The pump chamber 142 to be hermeticallysealed is in open communication with the inlet region 146 and the outletregion 144. The location of the inlet region 146 and the outlet region144 are such that there are essentially breaks in the assembly plane ofthe VAD 100. The sealing element 118 cannot adequately seal the inletregion 146 and the outlet region 144. Thus, hermetic sealing of theinterior of the VAD 100 relies in part on securing the tubing connectors128 and 130 to the upper clamshell half 114 and lower clamshell half 116at locations such as annular shoulders 137 and the like.

In addition, the configuration illustrated in FIG. 1 requires that theassembly faces of the upper clamshell half 114 and lower clamshell half116 be parallel to ensure pressure is imparted to the sealing element118 uniformly. This parallelism limits the range of design options forthe VAD 100 and results in the VAD 100 being larger and bulkier thannecessary, which is particularly disadvantageous when the VAD 100 isintended to be implantable in the patient.

In addition, the blood sac 122, valves 124 and 126 and the cannulaeconnected to the valves 124 and 126 via the tubing connectors 130 and132 are all constructed from a flexible material such as siliconerubber. Hence, these components are unstable during the handling andmanipulation required for assembling the components together prior toenclosing them between the upper and lower clamshell halves 114 and 116.Once filled with fluid, these components are easy to deform, makingproper handling and manipulation even more difficult.

Therefore, there is a need for providing a fluid pumping device thatprovides an improved static seal. There is also a need for providing afluid pumping device that does not require parallel assembly faces andthat is easier to assemble and disassemble. Further, there is a need forimproving the stability of a fluid pumping device during assembly anddisassembly.

SUMMARY

To address the foregoing problems, in whole or in part, and/or otherproblems that may have been observed by persons skilled in the art, thepresent disclosure provides methods, processes, systems, apparatus,instruments, and/or devices, as described by way of example in thevarious implementations set forth below.

According to one implementation, a static seal structure for a fluidpump housing includes a support structure, a first sealing element, anda second sealing element. The support structure circumscribes a pumpchamber. The support structure includes a first sealing side, a secondsealing side opposite to the first sealing side, a first opening locatedat the first sealing side, a second opening located at the secondsealing side, a first sealing surface circumscribing the first opening,a second sealing surface circumscribing the second opening, a fluidtransfer end interposed between the first sealing side and the secondsealing side, a fluid inlet bore formed through the fluid transfer end,and a fluid outlet bore formed through the fluid transfer end. Thesupport structure provides a fluid flow path running through the fluidtransfer end and into the pump chamber via the fluid inlet bore and fromthe pump chamber back through the fluid transfer end via the fluidoutlet bore. The first sealing element is disposed on the first sealingsurface, and the second sealing element is disposed on the secondsealing surface. The first sealing element and the second sealingelement are configured for forming sealed interfaces between the supportstructure and the fluid pump housing when assembled in the fluid pumphousing.

According to another implementation, a fluid pump housing includes asupport structure, a first sealing element, a second sealing element, afirst housing section and a second housing section. The supportstructure circumscribes a pump chamber. The support structure includes afirst sealing side, a second sealing side opposite to the first sealingside, a first opening located at the first sealing side, a secondopening located at the second sealing side, a first sealing surfacecircumscribing the first opening, a second sealing surfacecircumscribing the second opening, a fluid transfer end interposedbetween the first sealing side and the second sealing side, a fluidinlet bore formed through the fluid transfer end, and a fluid outletbore formed through the fluid transfer end. The support structureprovides a fluid flow path running through the fluid transfer end andinto the pump chamber via the fluid inlet bore and from the pump chamberback through the fluid transfer end via the fluid outlet bore. The firstsealing element is disposed on the first sealing surface, and the secondsealing element is disposed on the second sealing surface. The firsthousing section contacts the first sealing element and covers the firstopening, and the second housing section contacts the second sealingelement and covers the second opening. The support structure, the firstsealing element, the second sealing element, the first housing section,and the second housing section cooperatively fluidly seal the pumpchamber from an environment external to the fluid pump housing, with thefirst sealing element forming a sealed interface between the firsthousing section and the support structure and the second sealing elementforming a sealed interface between the second housing section and thesupport structure.

According to another implementation, a fluid pump includes a supportstructure, a first sealing element, a second sealing element, a firsthousing section, a second housing section, and a pump unit. The supportstructure circumscribes a pump chamber. The support structure includes afirst sealing side, a second sealing side opposite to the first sealingside, a first opening located at the first sealing side, a secondopening located at the second sealing side, a first sealing surfacecircumscribing the first opening, a second sealing surfacecircumscribing the second opening, a fluid transfer end interposedbetween the first sealing side and the second sealing side, a fluidinlet bore formed through the fluid transfer end, and a fluid outletbore formed through the fluid transfer end. The first sealing element isdisposed on the first sealing surface, and the second sealing element isdisposed on the second sealing surface. The first housing sectioncontacts the first sealing element and covers the first opening, and thesecond housing section contacts the second sealing element and coversthe second opening. The pump unit is disposed in the pump chamber, andincludes a pump inlet fluidly communicating with the fluid inlet boreand a pump outlet fluidly communicating with the fluid outlet bore. Thesupport structure, the first sealing element, the second sealingelement, the first housing section, and the second housing sectioncooperatively fluidly seal the pump chamber and the pump unit from anenvironment external to the fluid pump housing, with the first sealingelement forming a sealed interface between the first housing section andthe support structure and the second sealing element forming a sealedinterface between the second housing section and the support structure.

According to another implementation, a method is provided for forming astatic seal in a fluid pump housing. A support structure is seated in afirst housing section such that a first sealing element is interposedbetween a first sealing surface of the support structure and a firstinside surface of the first housing section. The support structurecircumscribes a pump chamber and the first sealing element circumscribesa first opening between the interior space and a first interior of thefirst housing section. A second housing section is seated on the supportstructure such that a second sealing element is interposed between asecond sealing surface of the support structure and a second insidesurface of the second housing section. The second sealing surface islocated on a side of the support structure opposite to the first sealingsurface and circumscribes a second opening between the interior spaceand a second interior of the second housing section. The supportstructure, the first sealing element, the second sealing element, thefirst housing section, and the second housing section cooperativelyfluidly seal the pump chamber from an environment external to the fluidpump housing.

Other devices, apparatus, systems, methods, features and advantages ofthe invention will be or will become apparent to one with skill in theart upon examination of the following figures and detailed description.It is intended that all such additional systems, methods, features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood by referring to the followingfigures. The components in the figures are not necessarily to scale,emphasis instead being placed upon illustrating the principles of theinvention. In the figures, like reference numerals designatecorresponding parts throughout the different views.

FIG. 1 is an exploded perspective view of a known Ventricular AssistDevice (VAD).

FIG. 2 is an exploded perspective view of an example of a fluid pumpprovided in accordance with the present invention.

FIG. 3 is a perspective view of an example of a static seal structurethat may be provided with the fluid pump illustrated in FIG. 2.

FIG. 4 is a plan view from a sealing side of the support structureillustrated in FIG. 3.

FIG. 5 is an elevation view from one end of the support structureillustrated in FIG. 3.

FIG. 6 is an elevation view from a lateral side of the support structureillustrated in FIG. 3.

FIG. 7 is a perspective view of an example of a pump unit of the fluidpump illustrated in FIG. 2 installed with the support structureillustrated in FIG. 3.

FIG. 8 is a plan view from a sealing side of the pump unit and supportstructure illustrated in FIG. 7.

FIG. 9 is an elevation view from a fluid transfer end of the pump unitand support structure illustrated in FIG. 7.

FIG. 10 is a lateral side of the pump unit and support structureillustrated in FIG. 7.

FIG. 11 is a plan view illustrating the pump unit and support structureseated in a housing section.

FIG. 12 is a plan view illustrating the same housing section asillustrated in FIG. 11 but with the pump unit and support structureremoved.

FIG. 13 is a cross-sectional elevation view of an example of a one-wayvalve that may be utilized in the fluid pump illustrated in FIG. 2.

FIG. 14 is a cross-sectional perspective view of the one-way valveillustrated in FIG. 13.

FIG. 15 illustrates an example of the use of the fluid pump as a LeftVentricular Assist Device (RVAD).

FIG. 16 illustrates an example of the use of the fluid pump as a RightVentricular Assist Device (RVAD).

FIG. 17 illustrates an example of the use of two fluid pumps as aBi-Ventricular Assist Device (BIVAD).

DETAILED DESCRIPTION

FIG. 2 is an exploded perspective view of an example of a fluid pump 200provided in accordance with the present invention. In the illustratedexample, the pump 200 is adapted for use as a Ventricular Assist Device(VAD). As will become evident from the following description, however,the pump 200 is not limited to use as a VAD but rather may be utilizedas another type of implantable or non-implantable pump. Moreover, thepump 200 may be adapted for use in non-medical as well as medicalpurposes. The pump 200 generally includes a pump unit 202 and a pumphousing 210 that when assembled encloses and hermetically seals the pumpunit 202. The pump unit 202 generally may be any device adapted to admita volume of fluid into its interior through a pump inlet and dischargethe fluid through a pump outlet via a pumping action. The fluid may be aliquid, gas, slurry, suspension, or the like. In the present example ofa VAD, the pump unit 202 may be a flexible sac adapted for pumpingblood. The housing 210 includes a rigid support structure 212surrounding the pump unit 202, a first housing section 214, and a secondhousing section 216. The support structure 212 and housing sections 214and 216 may be constructed from any suitable rigid material such asvarious types of plastics, and may be fabricated by any suitable moldingor machining process.

In assembling the pump 200, the pump unit 202 is placed in the supportstructure 212 in fluid communication with an inlet tubing connector 222and an outlet tubing connector 224. The tubing connectors 222 and 224may be constructed from any suitable rigid material such as varioustypes of plastics and metals (e.g., stainless steel, titanium, etc.).The designation of one particular tubing connector 222 or 224 as beingan inlet and the other tubing connector 224 or 222 as being an outlet isarbitrary and given merely by example. The support structure 212 is thenplaced in sealing contact with the first housing section 214 and thesecond housing section 216 in a manner described below. The firsthousing section 214 and the second housing section 216 are then securedtogether by fasteners or any other suitable means, resulting in a fullyhermetically sealed pump 200. The tubing connectors 222 and 224 aresecured directly to the support structure 212 and independently of thefirst housing section 214 and the second housing section 216. The firsthousing section 214 and the second housing section 216 may includerespective surfaces 226 and 228 that form apertures after assembly toprovide access to the tubing connectors 222 and 224. Neither the pumpunit 202 nor the tubing connectors 222 and 224 need to be sealed tothese apertures to maintain a static seal.

FIGS. 3-6 illustrate the support structure 212 utilized to form a staticseal for a pump such as the pump 200 illustrated in FIG. 2.Specifically, FIG. 3 is a perspective view, FIG. 4 is a plan view from asealing side, FIG. 5 is an elevation view from one end, and FIG. 6 is alateral side view.

Referring to FIG. 3, the support structure generally includes a firstsealing side 302, an opposing second sealing side 304, and a wall 306between the first sealing side 302 and second sealing side 304. In thepresent context, the wall 306 may include a single, continuous wall, ormore than one wall where adjacent walls are adjoined. In either case,the wall 306 circumscribes an interior space 308 sized to receive thepump unit 202 (FIG. 2) and in part defining a sealed chamber of the pump200. The support structure 212 generally includes a fluid transfer end312, an end 314 opposite to the fluid transfer end 312, and opposinglateral sides 316 and 318 extending between the fluid transfer end 312and the opposing end 314. The support structure 212 also includes afirst sealing surface 322 at the first sealing side 302 and an opposingsecond sealing surface 324 at the second sealing side 304. The firstsealing surface 322 circumscribes a first opening 326 and the secondsealing surface 324 circumscribes a second opening 328. Each sealingsurface 322 and 324 may have a flat or rounded profile and may or maynot be provided in the form of a groove. More generally, the firstsealing surface 322 is configured to receive a first sealing element 332and the second sealing surface 324 is configured to receive a secondsealing element 334. The sealing elements 332 and 334 may be constructedof any suitable deformable or elastic material. The sealing elements 332and 334 may be structured as continuous loops of material. In thepresent example, the sealing elements 332 and 334 include curvedsections at the fluid transfer end 312 and opposing end 314 and straightsections along the lateral sides 316 and 318. The sealing elements 332and 334 together with the support structure 212 form a static sealstructure.

In one implementation, the support structure 212 and sealing elements332 and 334 form a multi-piece static seal structure. In thisimplementation, the sealing elements 332 and 334 are initiallyphysically separate components that are first placed in properly alignedor oriented contact with either the respective sealing surfaces 322 and324 or the corresponding inside surfaces of the housing sections 214 and216 prior to assembling the support structure 212 and housing sections214 and 216 securely together. In another implementation, the supportstructure 212 and sealing elements 332 and 334 are initially provided asa one-piece static seal structure prior to assembly with the housingsections 214 and 216. In this implementation, the sealing elements 332and 334 are initially affixed to the respective sealing surfaces 322 and324 by any suitable means. As one non-limiting example, the supportstructure 212 and sealing elements 332 and 334 may all be fabricatedtogether in situ in a double injection manufacturing process. Asappreciated by persons skilled in the art, the double injectionmanufacturing process enables dissimilar polymers or different polymericcomponents to be joined together. In other implementations, the sealingelements 332 and 334 may be bonded or adhered to the respective sealingsurfaces 322 and 324 by any other suitable means that does not impairthe deformability or elasticity of the sealing elements 332 and 334.

Continuing with FIG. 3, an inlet bore 342 and an outlet bore 344 areboth formed at the fluid transfer end 312 of the support structure 212in open communication with the interior space 308. The designation ofone of these bores 342 or 344 as being the inlet and the other bore 344or 342 as being the outlet is arbitrary and given merely by example. Theinlet bore 342 is oriented about an inlet axis 346 along which fluidflows through the fluid transfer end 312 into the pump unit 202 (FIG.2). The outlet bore 344 is oriented about an outlet axis 348 along whichfluid flows from the pump unit 202 and back through the fluid transferend 312. The inlet bore 342 and the outlet bore 344 may be configuredand positioned such that the inlet axis 346 and the outlet axis 348 areparallel to each other and lie in the same plane, as in the illustratedexample. In other implementations, the inlet axis 346 and the outletaxis 348 may be non-parallel. As also shown in FIG. 3, the inlet bore342 and the outlet bore 344 may be sized to receive tubing connectors222 and 224 (FIG. 2) of a standard size. The portion of the wall 306associated with the fluid transfer end 312 is tall enough to accommodatethe inlet bore 342 and the outlet bore 344. However, as shown in FIG. 3and further in FIG. 6, the first sealing element 332 and the secondsealing element 334 may be non-parallel in accordance with certainimplementations of the present invention. In this case, the wall 306 ofthe support structure 212 along the lateral sides 316 and 318 may taperfrom the height at the fluid transfer end 312 down to a lesser height atthe opposite end 314.

FIGS. 7-10 illustrate the pump unit 202 installed with the supportstructure 212. Specifically, FIG. 7 is a perspective view, FIG. 8 is aplan view from a sealing side, FIG. 9 is an elevation view from thefluid transfer end, and FIG. 10 is an elevation view from a lateralside.

Referring to FIG. 7, the pump unit 202 generally includes a structuralenclosure 702 enclosing a pump interior in fluid communication with apump inlet and a pump outlet. The specific configuration of the pumpunit 202 may depend on the particular application of the pump 200 andthe type of fluid to be pumped. In the present example of a VAD, atleast a portion of the enclosure 702 of the pump unit 202 is flexiblesuch that the internal volume of the pump unit 202 varies betweencontraction/expansion cycles of the enclosure 702. Accordingly, the pumpunit 202 may be configured similarly to the flexible blood sac describedabove in conjunction with FIG. 1. All or a portion of the pump unit 202may be constructed from a stipple elastomer such as silicone, and thepump unit 202 may have a generally rounded profile with no sharp orabrupt edges. Such a configuration is suitable for preventing damage toblood tissue during pumping. A one-way inlet valve 712 is connected tothe inlet of the pump unit 202, and a one-way outlet valve 714 isconnected to the outlet of the pump unit 202. The inlet valve 712 andthe outlet valve 714 thus fluidly communicate with the pump interior butare detachable from the pump inlet and pump outlet for replacement,cleaning, or the like. The interior space 308 (FIG. 3) defined by thesupport structure 212 is large enough to accommodate the inlet valve 712and the outlet valve 714. The ends of the inlet valve 712 and outletvalve 714 opposite to the pump unit 202 are attached to the respectivetubing connectors 222 and 224. The inlet valve 712 and outlet valve 714may be coupled to the pump unit 202 and tubing connectors 222 and 224 byany suitable means such as, for example, friction fit, threading,Luer-type fitting, etc.

The tubing connectors 222 and 224 may be securely mounted to the inletbore 342 and outlet bore 344 (FIG. 3) in any suitable sealed manner thatprevents fluid leakage from the interior space 308 through the inletbore 342 and outlet bore 344. In one example, the tubing connectors 222and 224 may include threads that mate with complementary threads formedon the inside surface of the inlet bore 342 and outlet bore 344. Becausethe inlet bore 342 and outlet bore 344 are formed through the one-piecesupport structure 212, instead of by assembly of two housing sectionstogether, the tubing connectors 222 and 224 are easily sealed againstthe inlet bore 342 and outlet bore 344 without risk of leakage.

When the various components are assembled as illustrated in FIG. 7, afluid flow path is established in which fluid enters the input tubingconnector 222 as indicated by an arrow, passes through the fluidtransfer end 312 of the support structure 212, flows through the inletvalve 712 and into the interior of the pump unit 202, flows out from thepump interior and through the outlet valve 714, passes back through thefluid transfer end 312, and exits the output tubing connector 224 asindicated by an arrow. In practice, an input conduit (not shown) may beconnected between the input tubing connector 222 and a suitable fluidsource, and an output conduit (not shown) may be connected between theoutput tubing connector 224 and a suitable fluid destination. In thecase of a VAD, the input and output conduits may be medical-gradecannulae attached to a patient's heart according to known surgicalprocedures.

Various components of the pump 200, such as for example the pump unit202, valves 712 and 714, cannulae, etc. may be fabricated or treated forspecific purposes such as to improve blood compatibility andnon-thrombogenicity. As examples, such components may be coated withlubricant, hydrophobic, antibacterial and/or antithrombotic coatings,including but not limited to PTFE coatings, heparin-bonded coatings,fluorinated coatings, treclosan and silver compound coatings,anti-calcification agent-releasing coatings, etc.

Referring to FIGS. 2, 7 and 8, it can be seen that the interior chamberof the pump 200, which includes the interior space 308 (FIG. 3)circumscribed by the support structure 212, is completed upon assemblyof the first housing section 214 to the second housing section 216 withthe support structure 212 interposed between these two housing sections214 and 216. During assembly, the first sealing element 332 is properlyseated against a complementary interior surface of the first housingsection 214, and the second sealing element 334 is properly seatedagainst a complementary interior surface of the second housing section216. Compression and consequent deformation of the first and secondsealing elements 332 and 334 between the support structure 212 and therespective first and second housing sections 214 and 216 results in theinterior chamber of the pump 200 being hermetically sealed. Thecomponents associated with the inlet and outlet fluidic lines (e.g., theinlet and outlet of the pumping unit 202, the inlet and outlet valves712 and 714, the inlet and outlet bores 342 and 344 of the supportstructure, and the tubing connectors 222 and 224) are still located in aposition considered advantageous in many implementations, includingapplications entailing ventricular assistance, i.e., in between twohousing sections 214 and 216 that are assembled together to enclose apump unit 202. Due to the illustrated configuration, however, thesecomponents do not break or interfere with the assembly planes associatedwith the housing sections 214 and 216. In particular, the tubingconnectors 222 and 224 are remote from and completely independent of thefirst and second sealing elements 332 and 334 that serve as the assemblyinterfaces of the structural components of the pump housing 210.Moreover, as further shown in FIG. 10, the static seal establishedaccording to the present invention does not require sealing interfacesto be parallel.

FIG. 9 illustrates that the inlet valve 712 and outlet valve 714 may beconfigured as one-way valves, such as through the use of two or moreflaps or leaflets 902 in each valve 712 and 714 configured for allowingfluid flow in a single direction. A further example of one-way valves isdescribed below in conjunction with FIGS. 13 and 14.

FIG. 10 illustrates an implementation in which the support structure 212is tapered such that the first sealing element 332 and second sealingelement 334 are positioned in a non-parallel relation. In this case, thepump unit 202 may protrude out from the first sealing side 302 and thesecond sealing side 304 of the support structure 212. The interiorprofiles of the first and second housing sections 214 and 216 (FIG. 2)may be configured to be just large enough to enclose the pump unit 202and provide some space for a gas (e.g. air) to be admitted into theinterior chamber of the pump 200 for activating the pumping action ofthe pump unit 202. Because the first sealing element 332 and secondsealing element 334 are not required to be parallel, the pump housing210 does not need to assume a more traditional cylindrical or box-likeshape. Instead, the pump housing 210 can be made smaller and occupy lessvolume, which is particularly useful in implantable applications.

FIG. 11 is a plan view illustrating the pump unit 202 and supportstructure 212 seated in a housing section 214 (or 216). The housingsections 214 and 216 may provide openings 1102 and 1104 for accessingthe tubing connectors 222 and 224, as well as features such as annularshoulders 1106 and 1108 for facilitating the connection of cannulae orother types of conduits to the tubing connectors 222 and 224. However,the tubing connectors 222 and 224 are not required to be sealinglycoupled to these openings 1102 and 1104 to form a static seal. Instead,the tubing connectors 222 and 224 may be securely coupled to the inletbore 342 and outlet bore 344 of the support structure 212, with thestatic seal being established by the sealing elements 332 and 334.

FIG. 12 is a plan view illustrating the same housing section 214 (or216) as illustrated in FIG. 11 but with the pump unit 202 and supportstructure 212 removed. Each housing section 214 and 216 may include aninside sealing surface 1202 configured for complete, uniform contactwith the corresponding sealing element 332 or 334. The inside sealingsurface 1202 may have a flat or rounded profile and may or may not beprovided in the form of a groove. The inside sealing surface 1202 may bea continuous surface to ensure uniform contact with, and pressureimparted to, the sealing element 332 or 334. As also illustrated in FIG.12, the housing sections 214 and 216 may include shoulders or ridges1204 and 1206 proximate to their corresponding inside sealing surfaces1202 to facilitate seating the rigid support structure 212 (FIG. 11) inan aligned manner that ensures the establishment of a proper sealinginterface. As also shown in FIG. 12, at least one of the housingsections may include a gas (e.g., air) port 1212 and associated fitting1214 for connection to a pneumatic drive unit (not shown). As describedearlier, the pneumatic drive unit or equivalent device may be operatedto inject a gas into the chamber of the pump 200 in a pulsed manner toactivate the pumping action of the pump unit 202 (FIG. 11).

The pump 200 may be easily assembled and disassembled. As an example ofassembling the pump 200, the tubing connectors 222 and 224 are securedto the respective inlet bore 342 and outlet bore 344 of the supportstructure 212. The inlet valve 712 and outlet valve 714 may then beconnected to the respective inlet and outlet of the pump unit 202 and tothe corresponding tubing connectors 222 and 224. The support structure212 (with the associated components mounted thereto) may then be placedin contact with the appropriate inside surface 1202 of one of thehousing sections 214 and 216, with one of the sealing elements 332 and334 being interposed between the support stricture 212 and the housingsection 214 or 216. The other housing section 216 or 214 may then bebrought into contact with the opposing sealing side of the supportstructure 212, with the other sealing element 334 or 332 beinginterposed between the support structure 212 and the housing section 216or 214. The housing sections 214 and 216 are then secured or fastenedtogether by any suitable means, thereby compressing the sealing elements332 and 334 and establishing the fluid-tight, active static seal of thepump 200. Input and output cannulae (to other type of conduits) may beconnected to the corresponding tubing connectors 222 and 224 before orafter the housing sections 214 and 216 are secured to the supportstructure 212. In an implementation where one or both of the housingsections 214 and 216 include features adapted to enhance securement ofthe cannulae to the tubing connectors (e.g., shoulders, edges or thelike for effecting a crimping, clamping or locking action), the cannulaemay be connected to the tubing connectors 222 and 224 prior to securingthe housing sections 214 and 216 to the support structure 212. It canalso be seen that the support structure 212 provides a rigid componentfacilitating handling and manipulation of the various components duringassembly and disassembly. The support structure 212 may be directlyhandled by the user when attaching/detaching the inlet valve 712 andoutlet valve 714 to/from the pump unit 202 and tubing connectors 222 and224, and attaching/detaching the tubing connectors 222 and 224 to/fromcannulae.

FIG. 13 is a cross-sectional elevation view and FIG. 14 is across-sectional perspective view of an example of a one-way valve 1300that may be utilized as the inlet and outlet valves described above. Itwill be understood, however, that various other configurations may beprovided for the one-way valves utilized in the presently describedimplementations. In the present example, the one-way valve 1300 may havea hinge-less design in which two or more flexible, elastic flaps orleaflets 1302 and 1304 extend generally toward each other from an insidesurface of a main valve body 1306. The flaps 1302 and 1304 arepositioned between an inlet end 1312 and an outlet end 1314 of theone-way valve 1300. The flaps 1302 and 1304 are shaped such that whenthe fluid pressure at the inlet end 1312 is greater than the fluidpressure at the outlet end 1314, the flaps 1302 and 1304 flex away fromeach other whereby fluid flows from the inlet end 1312 to the outlet end1314. When the fluid pressure at the inlet end 1312 is less than thefluid pressure at the outlet end 1314, the flaps 1302 and 1304 arecompressed together whereby fluid is prevented from flowing from theoutlet end 1314 back toward the inlet end 1312. The one-way valve 1300is configured such that the opening and closing of the flaps 1302 and1304 is gentle and enables a smooth and continuous flow of fluid in theintended direction and in a manner similar to the action of a naturalheart valve. The one-way valve 1300 may be configured without any sharpedges and the material may be a supple elastomer such as, for example,silicone. The one-way valve 1300 may be formed by injection molding orany other suitable method of fabrication. A one-way valve such asillustrated in FIGS. 13 and 14 minimizes or eliminates the risk ofdamage to blood cells and hence is suitable for flowing blood.

As further illustrated by example in FIG. 13, the one-way valve 1300 mayinclude inside annular shoulders or surfaces 1322 and 1324 sized to abutthe respective ends of an inlet conduit 1326 and an outlet conduit 1328.It will be appreciated, however, that alternative couplingconfigurations may be implemented. In a case where the one-way valve1300 is utilized as an inlet valve, the inlet conduit 1326 may representan inlet tubing connector and the outlet conduit 1328 may represent theinlet of a pump unit. In a case where the one-way valve 1300 is utilizedas an outlet valve, the inlet conduit 1326 may represent the outlet of apump unit and the outlet conduit 1328 may represent an outlet tubingconnector.

FIGS. 15-17 illustrate examples of applications of the pump 200described above. FIG. 15 illustrates the use of the pump 200 as a LeftVentricular Assist Device (LVAD). A ventricular (or atrial) cannula 1502is attached to the input tubing connector of the pump 200 and surgicallyattached to an appropriate site of a patient's heart 1504, therebyproviding a flow path for blood from the heart 1504 into the pump 200.An arterial cannula 1506 is attached to the output tubing connector ofthe pump 200 and surgically attached to an appropriate site of the heart1504, thereby providing a flow path for blood from the pump 200 into theheart 1504. A pneumatic line 1508 is interconnected between the pump 200and a pneumatic drive device or equivalent gas (e.g., air) source 1702(FIG. 17) to provide a pulsed flow of gas for actuating the pump 200 asdescribed above. FIG. 16 illustrates the use of the pump 200 as a RightVentricular Assist Device (RVAD). FIG. 17 illustrates the use of twopumps 200 as a Hi-Ventricular Assist Device (BIVAD). The two pumps 200are driven by the pneumatic drive device 1702 via respective pneumaticlines 1708 and 1718.

FIGS. 15-17 illustrate examples of extracorporeal applications of thepump 200. It will be appreciated, however, that the pump 200 may beutilized in paracorporeal implementations and as a tethered implant. Asnoted above, the pump 200 is configured in accordance with the presentinvention such that its size may be reduced relative to pumps ofconventional design, thereby greatly facilitating implantableimplementations. The pump 200 may be utilized in a wide variety ofcirculatory supporting applications, including short-termtrans-operative support (e.g., a few hours), acute and post-cardiotomysupport (e.g., up to a few weeks), bridge to transplant (e.g., three tosix months), bridge to recovery (e.g., several years), and destinationtherapy (i.e., until death). More generally, the pump 200 may beutilized in various non-medical as well as medical applications forpumping various types of fluids. In addition to the flexible-sacconfiguration described by example above, other types of pump units maybenefit through the use of the static seal provided by the presentinvention.

In general, terms such as “communicate” and “in . . . communicationwith” (for example, a first component “communicates with” or “is incommunication with” a second component) are used herein to indicate astructural, functional, mechanical, electrical, signal, optical,magnetic, electromagnetic, ionic or fluidic relationship between two ormore components or elements. As such, the fact that one component issaid to communicate with a second component is not intended to excludethe possibility that additional components may be present between,and/or operatively associated or engaged with, the first and secondcomponents.

It will be understood that various aspects or details of the inventionmay be changed without departing from the scope of the invention.Furthermore, the foregoing description is for the purpose ofillustration only, and not for the purpose of limitation—the inventionbeing defined by the claims.

1. A method for forming a static seal in a fluid pump housing, themethod comprising: seating a support structure in a first housingsection such that a first sealing element is interposed between a firstsealing surface of the support structure and a first inside surface ofthe first housing section, the support structure circumscribing a pumpchamber and the first sealing element circumscribing a first openingbetween the interior space and a first interior of the first housingsection; and seating a second housing section on the support structuresuch that a second sealing element is interposed between a secondsealing surface of the support structure and a second inside surface ofthe second housing section, the second sealing surface located on a sideof the support structure opposite to the first sealing surface andcircumscribing a second opening between the interior space and a secondinterior of the second housing section, wherein the support structure,the first sealing element, the second sealing element, the first housingsection, and the second housing section cooperatively fluidly seal thepump chamber from an environment external to the fluid pump housing. 2.The method of claim 1, further including securing an input tubingconnector to an inlet bore formed through the support structure, andsecuring an output tubing connector to an outlet bore formed through thesupport structure, the inlet bore and the outlet bore being locatedbetween the first opening and the second opening of the supportstructure.
 3. The method of claim 1, further including placing a pumpunit in the pump chamber such that a pump inlet of the pump unit is influid communication with an inlet bore formed through the supportstructure and a pump outlet of the pump unit is in fluid communicationwith an outlet bore formed through the support structure, the inlet boreand the outlet bore being located between the first opening and thesecond opening of the support structure.
 4. The method of claim 3,further including placing an inlet valve in fluid communication with thepump inlet and an outlet valve in fluid communication with the pumpoutlet, wherein the inlet valve is interposed between pump inlet and theinlet bore and the outlet valve is interposed between the pump outletand the outlet bore, and the inlet valve and the outlet valve arelocated between the first opening and the second opening of the supportstructure.
 5. The method of claim 4, further including securing an inputtubing connector to the inlet bore and securing an output tubingconnector to the outlet bore, wherein the input tubing connector fluidlycommunicates with the pump inlet via the inlet valve and the outputtubing connector fluidly communicates with the pump outlet via theoutlet valve.